Grinding apparatus



NOV. 14, 1967 KRUMHQLZ 5 3,352,501

GRINDING APPARATUS Filed March 31, 1965 2 Sheets-Sheet l FgLg i U L 4'7| I 70 I Inventor V I JHfr ed Flirumholgsr.

' .flfiornegfi United States Patent 3,352,501 GRINDING APPARATUS AlfredF. Krumholz, Sr., Glenview, Ill., assignor to Chicago Boiler Company,Chicago, 111., a corporation of Illinois Filed Mar. 31, 1965, Ser. No.444,361 8 Claims. (Cl. 241-74) ABSTRACT OF THE DISCLOSURE A sand or likegrinder having impellers, for grinding pigments and the like, is soconstructed as to enable the impeller shaft to be easily removed forcleaning.

This invention relates to apparatus for dispersing particulate solids ina liquid media and/ or reducing the size of the particles.

The present invention is particularly adapted for use with the so-calledsand grinding process ommonly employed to disperse and deagglomeratepigment in a liquid as described in US. Patent No. 2,855,156. Thisprocess has been employed with favorable results while using sand orother grinding media, for example steel balls, glass beads, etc. havealso been employed for dispersing and deagglomerating materials.Likewise, the process is used to deagglomerate and disperse a widevariety of materials or particulate solids other than pigments.

Heretofore, known commercial sand grinding apparatus, such asillustrated in US. Patent Nos. 2,855,156 and 3,050,263, have employed arotatable shaft driven from the top of a mixing vessel in which isdisposed the particular solids, grinding medium and liquid. Thisrotatable shaft carries a series of impellers which agitate the mixtureto disperse and deagglomerate the particulate solids. Either at the topor the bottom of the vessel a screen is employed to separate thegrinding media from the mixture of particular solids and liquids beingdischarged through an outlet from the vessel.

In some instances the rotatable shaft is directly connected to a motorsupported at the top of the vessel and in other instances the shaft isdriven by a drive belt or chain at the top of the vessel leading to amotor. In any event, some difliculties, although admittedly notinsurmountable, have been experienced in either type of arrangement whenit is desired to clean or service the vessel such as when changing thecolor or pigment, type of grinding media or screen employed therein, andthe primary object .of the present invention is to so construct grindingapparatus as to facilitate cleaning and servicing. More specifically, anobject of the invention is a mixing vessel having the top thereofunencumbered by a drive mechanism and having a rotatable impeller shaftextending through the bottom of the vessel for connection to a drivemechanism.

A common occurrence with grinding apparatus of the type exemplified bythe above-identified prior art is that the screen for separating thegrinding media from the discharged material becomes clogged or coveredwith dried or solidified material which reduces the flow rate ofdischarge. Also when changing materials or pigments it is many timesrequired that the screen be replaced by a screen of different size or bya screen free of such dried material. Accordingly, another object of thepresent invention is to construct a sand grinding machine with aremovable upper cover unhampered by a motor for the rotatable shaft topermit ready access to the separating screen.

A further problem with grinding apparatus, as exemplified by the abovecited patents, is that deposits of grinding media tend to accumulate onthe tops of the disks or impellers. Flushing with a cleaning solvent orrotation of the impeller shaft without fluid medium in the vessel hasnot proved satisfactory in removing such deposits. Rotation of the shaftwithout a fluid in the vessel is an undesirable practice because theunsecured lower end of the shaft wobbles and can result in damage to theshaft and to the bearings for the shaft. Accordingly, a further objectof the present invention is a sand grinding apparatus in which theimpeller shaft can be readily removed outwardly from the top of thevessel without dismantling of the drive for the shaft so that theimpellers and the interior of the vessel can be readily serviced orcleaned.

Because of the particular abrasive nature of the sand pigments andparticular solids and the penetrating ability of solvents and otherliquids used Within the grinder, it has heretofore been a particularlydiflicult problem to afford a tight shaft seal at the top of the vessel,no less at the bottom of the vessel. Accordingly, a further object ofthe invention is a new and improved shaft seal and drive apparatus forthe rotatable shaft of the grinding apparatus capable of withstandingsuch severe operating conditions.

Another object of this invention is to construct sand grinding apparatushaving an upper bearing protected by a shaft seal and a lower driveshaft extending upwardly through the bottom of the vesel for connectionto the rotatable impeller shaft, the drive shaft being protected by aseal; and a further object is to facilitate service and repair of suchapparatus by having the shaft seal for the drive shaft removable withthe impeller shaft.

Other and further objects of the present invention will be apparent fromthe following description and claims and are illustrated in theaccompanying drawings which, by way of illustration show preferredembodiments of the present invention and the principles thereof and whatis now considered to be the best mode contemplated for applying theseprinciples. Other embodiments of the invention embodying the same orequivalent principles may be used and structural changes may be made asdesired by those skilled in the art without departing from the presentinvention.

In the drawings:

FIG. 1 is a sectional view showing a grinding apparatus incorporatingthe preferred embodiment of the invention;

FIG. 2 is an enlarged sectional view of the upper end of the impellershaft and shaft seal;

FIG. 3 is an enlarged sectional view of the drive shaft and itsconnection to the impeller shaft and of the shaft seal for the driveshaft;

FIG. 4 is a view taken along the line 44 of FIG. 1 in the direction ofthe arrows showing the mounting of the drive motor;

FIG. 5 is a sectional view taken along the line 55 of FIG. 4 showing thepivotal mounting of the motor for controlling tension in a drive belt;and

FIG. 6 is a sectional view taken along the line 66 of FIG. 4 showing themounting of the drive motor.

Referring now to the drawings and more particularly to FIG. 1 there isillustrated a sand grinding apparatus incorporating thepreferred-embodiment of the invention. The sand grinding apparatus has agenerally fiat base 10, an upstanding plate 11 on the base 10 forholding a cylindrical vessel 12 in which is dispersed and deagglomeratedparticulate solids or the like. The vessel 12 is usually verticallyoriented in a generally vertical direction with an impeller shaft 14disposed on the vertical axis at the center of the cylindrical vessel12. The rotatable shaft 14 has a series of impellers 15 secured theretofor agitating and mixing the sand and slurry within the vessel 12.

In the grinding apparatus herein described, a slurry mixture consistingof a particulate solid such as a pigment and a fluid or film-formingvehicle would enter through an inlet pipe 18 disposed at the bottom ofthe vessel 12. The grinding media such as sand would already be withinthe vessel for mixing with the incoming slurry. The lower interiorportion of the vessel 12 is defined by an inner cylindrical wall portion20, which is surrounded by an annular cooling jacket formed between thewall 20 and the lower portion of an outer cylindrical wall 21 of thevessel 12. Cooling water enters between the walls 20 and 21 through aninlet pipe 22 and is circulated to cool the surface of the cylindricalwall 20 and exits at the top through an outlet pipe 24.

As the sand and slurry mixture is agitated by the impellers 15, the sandand slurry is forced upwardly into an annular chamber 25 formed within acylindrical screen member 26 which serves to separate the grinding mediafrom the slurry. The now mixed and dispersed slurry mixture is forcedthrough the screen member 26 into an annular space 30 about the screenmember 26 for exiting through an outlet pipe 32 at the top of the vessel12. The screen member 26 has secured about its upper and lowerperipheral edges a pair of spaced sealing rings 27 and 28. The sealingring 27 is in tight sealing engagement with a flange 29 on thecylindrical wall 20 to prevent the leakage of the grinding media orslurry between the flange 29 and screen member 26. Likewise, the topcover plate 35 tightly engages the upper sealing ring 28 to preventleakage of grinding media or slurry from the top edge of the screenmember 26.

It will be appreciated that the screening member 26 can be completelycylindrical or semi-cylindrical or of various sizes and shapes. Also,the size of the screen openings can be selected either for theparticular type of grinding media involved, such as 'sand or balls oflarger diameter than the grains of sand; or the screen can be selectedfor the type and viscosity of the slurry mixture. After considerableusage, the screen often becomes clogged with particles. Typically, suchclogging is caused 'by the accumulation of particles which have not beenground sufficiently to pass through the screen or by the drying ofliquids on the screen. Thus, when changing the type of grinding media orchanging the type of materials being ground, such as different colors ofpigment, it is often necessary or most desirable to afford ready accessto the interior of the vessel 12. For instance, the screen member 26 mayneed to be cleaned of colored pigments or replaced by a screen memberhaving a different size of screen openings.

An important aspect of the present invention is the facilitating ofaccess to the screen and to the interior of the vessel 12. A problemwith prior art apparatus of the general type hereinbefore described isthat the drive for the impeller shaft such as the shaft 14 was from thetop of the vehicle and required a complete dismantling or at least apartial dismantling of the drive; and often required removal of aportion of the drive from above the impeller shaft 14 before the topcover could be lifted to afford the needed access to the interior of thevessel. However, under the present invention a top cover35 may be easilyand quickly detached by loosening fasteners 36 and lifting the coverplate 35 directly from the top of the shaft 14. As best seen in FIG. 2,

the upper end of the shaft 14 is reduced in diameter at 38, this smallerdiameter portion 38 being disposed for rotation within a bearing 39carried in a seal housing 40 welded or otherwise secured to the topplate 35. The bearing 39 rests on an annular shoulder 41 formed in thebore 42 of the seal housing 40. An end cap 44 is threaded into the topportion of the seal housing 40. The end cap 44 seals the bore 42 againstthe exhausting 42 in the housing 40.

The seal housing 40 has an inner cavity or chamber 45 of upwardlytapering configuration towards the bearing 39. The decreasing diameterof the annular chamber 45 enhances the compressing and trapping of airwithin the chamber of space 45 upon the initial entry of sand and slurrymixture into the lower portion of, the air chamber 45. This compressedair serves as a sealing means for preventing the movement of the sandand bearing 39 may "be a solid bearing of plastic, bronze,

babbitt; or may be a ball or roller bearing.

Inspection, servicing or repair of the interior of the sand grinder isfacilitated by removal of the top plate 35 and bearing 39 from the endof the shaft 14. Thus, the interior of the sand grinder is exposed forservicing or the like. When using sand and certain other types ofgrinding media, stopping of the rotation of the shaft 14 tends todeposit grinding media on the tops of the impellers 15. This depositedgrinding media is diflicult to remove from the impellers 15 withoutremoval of the shaft 14 and its attached impellers 15. Thus, in manyinstances, it is desired to lift the impeller shaft 14 and to remove theshaft 14 and its impellers 15 for cleaning.

The removal of the impeller shaft 14 is facilitated under the presentinvention not only by elimination of an upper drive for the impellershaft, as hereinbefore described, but also by the manner of readydisconnection of the impeller shaft 14 from a drive shaft 50 extendingupwardly through a bottom plate 51 at the bottom of the vessel 12.

As best seen in FIG. 3, the lower end of the, shaft 14 has a coupling 52secured thereto as by welding. The coupling 52 has a generally squaresocket or internal cavity 53 formed by intersecting flat side walls. Acomplementary or mating square end 55 of the shaft 50 extends ortelescopes into the coupling cavity 53. Thus, rotation of the driveshaft 50 causes rotation of the shaft of the impellers 14 through thecoupling 52 wherein the square drive shaft 55 is fitted into thecomplementary square shaped cavity 53.

g The drive shaft 50 'is journaled for rotation in the upper bearing57.and in a pair of lower bearings 58 and 59 held in a bracket 60. Theupper bearing 57 is preferably a flange type of bearing having an upperflange 62 serving as a thrust bearing for the coupling 52 and thereby athrust bearing for the impeller shaft 14. The flange 62 of the bearing57 rests on the upper annular surface 64 of a cylindrical bearinghousing 66 preferably secured as by welding to the lower plate 51. Thebearing 57 is fitted Within the circular opening 67 of the bearinghousing 66. Also a packing 68 may be disposed against the bottom surfaceof the bearing 57 and about the drive shaft 50.

The packing 68 or mechanical seal is compressed between the bottom ofthe upper bearing '57 and the top shoulder of an annular gland 70 whichis secured by cap screws 71 to the bottom plate 51. The packing 68 ormechanical seal serves to prevent the loss of air from a sealing means,described hereinafter. This sealing means the side wall 74 of the bellshaped member 75 of the coupling 52. Preferably, both the side walls 72and 74 are tapered to assist in the compressing of air by afford- 1ng asmaller and smaller annular cavity for the air as the slurrymixture'moves upwardly into the air chamber to further compress the airtherein. That is, upon the initial charge of slurry, the slurry willmove upwardly between the side walls 72 and 74 until stopped by thetrapped air, now compressed, at the top portion of the annular air spacewhich thereafter serves as a seal to prevent contamination of thebearing 57 by either the sand or slurry mixture. The compressed air sealalso prevents the escape of the slurry out of the sand grinder along theshaft 50. The packing 68 or mechanical seal serves to hold thecompressed air from exiting along the shaft 50 of the sand grinder. Ifit is warranted, a compressed air conduit can be afforded in the bearinghousing 66 leading to the annular air chamber formed by side walls 72and 74 to assist in maintaining the compressed air serving as thesealing means. Also it is to be understood that either one or both ofthe surfaces 72 may be tapered or not tapered, as preferred, so long asthe compressed air chamber is formed therebetween to protect the bearing62.

Collars 84 and 85 are secured to the drive shaft 50 and spaced toaccommodate the bearings 58 and 59 against which the collars 84 and 85engage, respectively, with vertical movements of the drive shaft 50.Thus, the bearings 58 and 59 function as thrust bearings for the driveshaft 56. The bearings 58 and 59 are held by the bracket 60 having agenerally vertical extending arm 90 secured by fasteners 91 to-thebottom of the vessel 12.

The manner of mounting the vessel 12 and the motor M on the upstandingsupporting plate 11 is more readily apparent from a consideration ofFIGS. 1, 4, 5 and 6. As best seen in FIGS. 1 and 5, the outer wall 21 ofthe vessel 12 is secured to a vertically oriented plate 95 by a pair ofvertically extending gussets 96 and 97 each of which is welded along oneedge to the cylindrical wall 21 and along the other edge to the supportplate 95. Bolt and nut fasteners 98 are inserted through alignedapertures in the plates 95 and 11 and are tightened to detachably mountthe vessel 12 to the upstanding plate 11 on the base 10.

The upstanding plate 11 is bent at right angles at the vertical edgesthereof to form a pair of rearwardly extending gussets 100, FIG. 1, ofgenerally triangular shape which extend rearwardly from the vessel 12and plate 11. The gussets 100 are welded along bottom edges thereof tothe top plate of the base 10. Thus, the gussets 100 and the upstandingplate 11 constitute a generally U-shaped support, FIG. 5, within whichis disposed the mounting bracket 105 for the motor 83.

The motor 83 is secured by bolts 106, FIG. 4, to a mounting member 108having an inwardly turned, upper flange 109 and an inwardly turned,downward flange 110. The upper flange 109 is adapted to rest on ahorizontal leg of an angle brace 112 welded or otherwise secured to therear of the upstanding plate 11. The inward turned flange 110 isdisposed for cooperation with a horizontal leg of an angle 113 welded orotherwise secured to the rear surface of the upstanding plate 11.

For control of tension of the drive belts 80 on the sheaves 78 and 81,it is preferred that the motor 83 be pivotally mounted by its bracketmeans 105. Hence, the motor shaft 82 can be moved to the drive shaft 50to loosen the drive belts 80 so that the belts 80 can be removed.Conversely, the drive shaft 50 can be moved to tighten the drive beltsto their proper tension. For this purpose the support member 108 ispivotally mounted by studs 115 and 116 to the respective angle brackets112 and 113 and slots such as 118, FIG. 5, are formed to receive lockingbolts 119 and 120 to lock the bracket 105 against pivotal movement aboutthe studs 115 and 116 while preventing pivotal movement of the motor 83thereabout.

To afford a relatively fine adjustment when tensioning the drive belt80, the support member 108 has a nut 123 welded thereto through which isthreaded a bolt 124.

6 Thus, turning of the bolt 124 in the nut 123 in one direction willpermit the swinging of the motor 83 toward the upstanding plate 11 toloosen the drive belts 80, and turning of the bolt 124 in the oppositedirection will exert a force on the belts to tension or tighten thebelts 80 to the requisite degree required.

From the foregoing, it will be seen that the present invention affords anovel grinding apparatus having a bottom drive facilitating the removaland cleaning of the interior of the grinding apparatus withoutdisconnecting or dismantling the screen member such as 26 could beemployed at the bottom of the vessel and still be retained ,accessablefor removal and inspection without necessitating disconnecting the driveat the top of the lever as was heretofore the practice.

Hence, while preferred embodiments of the invention have been describedand illustrated, it is to be understood that they are capable ofvariation and modification.

I claim:

1. Apparatus for the deagglomerating and dispersing of particulatesolids in a liquid by a means of a grinding medium comprising: anupright vessel for a mixture of the grinding medium liquid and solidstherein, a top plate means at the top of said vessel and detachabletherefrom, a bottom plate means on said vessel, an impeller shaft meansextending vertically downward from said top plate means and journaledfor rotation in said top plate means, a screen means in said vesseladjacent an outlet from said vessel for screening the grinding mediumfrom the mixture of particulate solids and the liquid, a drive shaftmeans extending upwardly from the bottom plate means and adapted to berotated, coupling means for coupling said drive shaft means to saidimpeller shaft means for rotating said impeller shaft means with saiddrive shaft means, sealing means for sealing said drive shaft means forpreventing the flow of particular solids, grinding medium or liquid,downwardly along said drive shaft means and from said vessel, and drivemeans for driving said shaft.

2. Apparatus of claim 1 wherein said coupling means has a socket forreceiving a portion of said driving shaft means, said impeller shaftmeans and said drive shaft means adapted for disconnection upon removingsaid socket from said portion of said drive shaft means.

3. Apparatus of claim 1 wherein said sealing means includes an airchamber for trapping air under pressure to prevent movement of saidparticulate solids past said air chamber and along said drive shaftmeans.

4. Apparatus of claim 1 wherein said drive means includes a drivingmotor spaced from said drive shaft means, and belt means extendingbetween said driving motor and said drive shaft means for rotating saiddrive shaft means.

5. Apparatus for deagglomerating and dispersing particulate solids inliquids by a grinding medium comprising: a generally cylindrical vesselhaving an inlet for introduc ing a mixture of particulate solids andliquids under pressure and having an outlet for discharge of dispersedand ground particles in said liquid, a screen means in said vessel forseparating said grinding medium from said dispersion intended for saidoutlet, a separate top access plate on said vessel, an air bell securedto said top plate, a rotatable impeller shaft means extending into saidair bell and downwardly into said vessel for agitating said mixture andgrinding medium, a top bearing for said impeller shaft means disposedoutwardly of said air bell which serves as a shaft seal to prevent theentrance of said solids, liquids or grinding medium into said topbearing, a bottom plate on said vessel having an opening therein, adrive shaft extending upwardly through said opening in said bottomplate, coupling means coupling said drive shaft to said impeller shaftmeans, means for sealing said drive shaft at said opening in said bottomplate, and drive means for driving said drive shaft.

6. Apparatus of claim 5 including a bearing support secured to saidbottom plate, a bearing supported on said bearing plate and having aportion thereof serving as a thrust bearing surface 'for therotatableimpeller shaft means, said sealing means sealing said bearingagainst contamination by said grinding medium, particulate solids orliquids.

7. Apparatus of claim 5 including a bracket means, a bearing means forsaid drive shaft secured in said bracket means for journaling thereinsaid drive shaft.

8. Apparatus of claim 5 including a support means, said driving meansincluding a motor mounted on said support means for pivotal movement onsaid support means, means to lock said motor means in a pivotalposition, and driving belt means extending between said motor means andsaid drive shaft for driving said drive shaft and said impeller shaftmeans to deaggl'o'rnerate and disperse said particulate solids in saidliquid.

References Cited UNITED STATES PATENTS Hoxt.

Fuller 24174 Ahlr'nann 241-172 X Tr'ede a 30836.3 Schwaneke 259108Rohling'er E 241-74 De Gail 24174 Norris 241179 Goeser 24174 X Tight241- 172 X FOREIGN PATENTS ANDREW R. JUHASZ, Primary Examiner.

HARRY F.7PEPPER, JR., Examiner.

1. APPARATUS FOR THE DEAGGLOMERATING AND DISPERSING OF PARTICULATE SOLIDS IN A LIQUID BY A MEANS OF A GRINDING MEDIUM COMPRISING: AN UPRIGHT VESSEL FOR A MIXTURE OF THE GRINDING MEDIUM LIQUID AND SOLIDS THEREIN, A TOP PLATE MEANS AT THE TOP OF SAID VESSEL AND DETACHABLE THEREFROM, A BOTTOM PLATE MEANS ON SAID VESSEL, AN IMPELLER SHAFT MEANS EXTENDING VERTICALLY DOWNWARD FROM SAID TOP PLATE MEANS AND JOURNALED FOR ROTATION IN SAID TOP PLATE MEANS, A SCREEN MEANS IN SAID VESSEL ADJACENT AN OUTLET FROM SAID VESSEL FOR SCREENING THE GRINDING MEDIUM FROM THE MIXTURE OF PARTICULATE SOLIDS AND THE LIQUID, A DRIVE SHAFT MEANS EXTENDING UPWARDLY FROM THE BOTTOM PLATE MEANS AND ADAPTED TO BE ROTATED, COUPLING MEANS FOR COUPLING SAID DRIVE SHAFT MEANS TO SAID IMPELLER SHAFT MEANS FOR ROTATING SAID IMPELLER SHAFT MEANS WITH SAID DRIVE SHAFT MEANS, SEALING MEANS FOR SEALING SAID DRIVE SHAFT MEANS FOR PREVENTING THE FLOW OF PARTICULAR SOLIDS, GRINDING MEDIUM OR LIQUID, DOWNWARDLY ALONG SAID DRIVE SHAFT MEANS, AND FROM SAID VESSEL, AND DRIVE MEANS FOR DRIVING SAID SHAFT. 